1. Field of the Invention
The present invention relates to an automotive alternator mounted to, for example, an automotive vehicle, and, in particular, to an automotive alternator mounting a brush, rectifier and regulator.
2. Description of the Related Art
FIG. 19 is a cross section showing a conventional automotive alternator for use in an automobile. FIG. 20 is a perspective view of the conventional alternator. The conventional automotive alternator shown in the figures includes, a case 3 constructed from an aluminum front bracket 1 and rear bracket 2, a shaft 5 with a pulley 4 fixed on one end thereof provided inside the case 3, a claw-pole rotor 6 fixed to the shaft 5, fans 7a, 7b fixed on respective axial end surfaces of the rotor 6, a stator core 17 fixed inside the case 3, a stator coil 18 received in slots of the stator core 17, a stator 8 constructed from the stator core 17 and the stator coil 18, a slip-ring 9 fixed on the other end of the shaft 5 for supplying electric current to the rotor 6, a pair of brushes 10 for slidingly contacting the slip-ring 9, a brush holder 11 for receiving the brushes 10, a rectifier 12 electrically connected to the stator coil 18 for rectifying an alternating current (ac) produced in the stator coil 18 into a direct current (dc), a heat sink 13 fitted to the brush holder 11, and a regulator 14 attached to the heat sink 13 for adjusting the alternating voltage produced in the stator coil 18.
A connector 22 for insertion in an external plug (not shown) is disposed in the vicinity of the regulator 14. A regulator assembly 30 includes the regulator 14, brush holder 11 and connector 22.
The rotor 6 includes a rotor coil 15 for flowing an electric current to generate magnetic flux and a pole core 16 which houses the rotor coil 15 and forms magnetic poles in accordance with a magnetic flux. The fans 7a, 7b for cooling are provided on respective axial end surfaces of the pole core 16.
The stator 8 includes the stator core 17, through which passes a rotating magnetic field in accordance with the rotor 6, and the stator coil 18 which flows an alternating current output in accordance with the rotating magnetic field, and the stator coil 18 forms coil ends 19 at both axial ends of the stator core 17.
FIG. 21 is a perspective view of the regulator assembly 30. Moreover, FIG. 22 is a drawing showing front, top and side views of the regulator assembly 30. In the conventional regulator assembly 30, the regulator 14 and brush holder 11 are disposed so as to overlap in an axial direction of the shaft 5. The connector 22 is disposed relative to the regulator 14 and brush holder 11 at a location on a plane including the regulator 14 and brush holder 11 and orthogonally intersecting the shaft 5 and rotated a predetermined angle in a circumferential direction, and such that an opening thereof faces toward the outside. Ventilating holes 30a are provided at both sides of the brush holder 11.
FIG. 23 is a perspective view of the rectifier assembly 31 in which a rectifier 12 is assembled with a circuit board 29. Furthermore, FIG. 24 is a front view of a conventional rear bracket assembly. FIG. 25 is a cross section taken along the line Cxe2x80x94C shown by the arrows in FIG. 24. In the figures, the rectifier 12 includes diodes 20 mounted on an approximately C-shaped heat sink 21, and the rectifier 12 is assembled with a similarly roughly C-shaped circuit board 29 to give the rectifier assembly 31. The rectifier assembly 31 is assembled to the rear bracket 2 such that the circuit board 29 is positioned at the middle of the dynamo-electric generator (alternator). Further, the rectifier assembly 31 is secured by bolts 28 as a fixing means. In this case, since the rectifier assembly 31 makes a approximate C-shape, it is possible to have a space in a C-shaped opening. Next, the regulator assembly 30 is inserted and assembled in this space and, as shown in FIGS. 24 and 25, the rear bracket assembly is assembled. Moreover, an angle between the two bolts 28, being a standard governing the size of the plate-shaped heat dissipating heat sink 21, is 210 degrees.
FIG. 26 is a front view of a conventional rear bracket. FIG. 27 is a drawing of a conventional alternator viewed from a rear side thereof. A plurality of openings E (intake holes) formed in the rear bracket are opened at locations corresponding to the roughly C-shaped rectifier assembly 31. Moreover, an opening G (intake hole) is opened at a location corresponding to the regulator assembly 30.
In an automotive alternator constructed as above, as shown in FIG. 19, cooling air flows into the case 3 from the openings E of the case 3 in accordance with rotation of the fan 7b which rotates together with rotation of the rotor 6. This cooling air flows as shown by the arrow a and cools the heat sink 21 and diodes 20. Then, this cooling air is flowed in an outside radial direction (centrifugal direction) by the fan 7b and is discharged to the outside from an opening F. Moreover, cooling air also flows into the case 3 in accordance with rotation of the fan 7b from an opening G and this cooling air flows as shown by the arrow xcex2 and cools the heat sink 13 and power transistors of the regulator 14. Then, this cooling air is flowed in an outside radial direction by the fan 7b and is discharged to the outside from an opening H.
An S terminal, so-called because it relates to sensing, and an L terminal, so-called because it relates to a lamp, are provided in the connector 22 and these terminals are connected to various portions in an automotive vehicle via an external plug (not shown). The S terminal is used to monitor battery voltage and the L terminal is used to flow an initial exciting current and for lighting a lamp (not shown) when there is a generating abnormality such as an over generation, over discharge and the like.
In a conventional automotive alternator constructed as above, the regulator assembly 30 is disposed in the empty space of the C-shaped opening portion of the approximately C-shaped rectifier assembly 31. Namely, the rectifier assembly 31 and regulator assembly 30 are provided in a same plane orthogonally intersecting the shaft 5. Thus, the size of the heat sink 21 of the rectifier 12 is limited by the regulator assembly 30. However, if the size of the heat sink 21 of the rectifier 12 is increased, cooling characteristics of the rectifier 12 are improved and durability may also be increased along with the increase in performance. Also, the connector 22 is disposed, relative to the regulator 14 fixed to the heat sink and the brush holder, in the same plane orthogonally intersecting the shaft 5 and adjacent in a circumferential direction. Since there is a difference in ventilating resistance between the portions where the heat sink and connector 22 are disposed, the rectifying characteristics of the cooling air ventilating the regulator assembly 30 are obstructed. Consequently, the cooling characteristics of the entire rear bracket assembly, including the rectifier 12, are degraded. Moreover, wind noise increases due to a ventilating unbalance at the intake side.
The present invention aims to solve the above problems with the conventional art and an object of the present invention is to provide an automotive alternator in which a ventilating resistance unbalance is improved, surface area of a heat dissipating plate of a rectifier is enlarged to improved cooling characteristics of the rectifier and reduce noise, performance is high, and durability and quality are high.
In order to achieve the above object, according to one aspect of the present invention, there is provided an automotive alternator comprising:
a shaft supported in a case so as to be capable of rotating;
a rotor housed in the case and comprising a plurality of magnetic poles fixed to the shaft, a field winding, and fans fixed to at least one axial end of the magnetic poles; a stator fixed to the case so as to be positioned at an outer circumference of the rotor and comprising a core and a winding wound in the core, and provided with coil ends formed by bending back the winding at ends of the core;
a rectifier disposed in the case and comprising a rectifying element for rectifying an ac generated by the stator to a dc and a heat dissipating plate for dissipating heat generated by the rectifying element;
a regulator disposed in the case for adjusting a magnitude of the ac voltage generated by the stator;
a brush disposed in the case so as to advance and retreat in a radial direction of the rotor and one end thereof contacting the rotor to supply a field current to the field winding of the rotor;
a connector for mounting an external plug; and
the case containing a plurality of intake holes at a side where the fan of the rotor is mounted, and cooling air drawn in from the intake holes is bent in a centrifugal direction after cooling the rectifier to ventilate and cool the coil ends; wherein,
the regulator and the brush are disposed so as to overlap in an axial direction, and center lines of the regulator, the brush, and the connector are disposed on an approximately same plane extending in a radial direction, the rectifier is disposed approximately line symmetrical to the same plane, and the plurality of intake holes are formed in the case at a position corresponding to the rectifier.
According to another aspect of the present invention there is provided an automotive alternator wherein:
the regulator and the brush are disposed approximately point symmetrical with the connector with the shaft as a center, and center lines of the regulator, brush and connector are disposed on an approximately same plane extending in a radial direction.
According to yet another aspect of the present invention there is provided an automotive alternator wherein:
the connector is disposed at an approximately outer circumferential-side of the regulator and the brush, and center lines of the connector, the regulator and the brush are disposed on an approximately same plane extending in a radial direction.
According to still yet another aspect of the present invention there is provided an automotive alternator wherein:
the regulator and the brush are disposed so as to overlap in an axial direction, the connector is disposed so as to further overlap the regulator and the brush in an axial direction, and center lines of the regulator, the brush and the connector are disposed on an approximately same plane extending in a radial direction.
According to still yet another aspect of the present invention there is provided an automotive alternator wherein:
a fixing means for fixing to the case is used for both the regulator and the rectifier.
According to still yet another aspect of the present invention there is provided an automotive alternator wherein:
the coil end does not substantially lap the fan in an axial direction and the cooling air produced by the fan ventilates an end portion of the coil end.
According to still yet another aspect of the present invention there is provided an automotive alternator wherein:
the coil end substantially laps the fan in an axial direction and the cooling air produced by the fan passes through and ventilates an interior of the coil end.